In this article, which considering the history of philosophy is an example of how Christianity meets Hellenism, we drew the following conclusions, relying on Leontius of Byzantium’s treatise entitled Contra Nestorianos et Eutychianos:A) Throughout the entire approach, the Christian thinker uses both the philosophical concepts –such as “hypostasis”, “nature”, “universal”, “atom”, “form”, “subject”– and the arguments derived from the theoretical field of Logic in order to explain Christian questions, mostly related with Metaphysics. He is actually quite an eclecticist and that is why we may not allege that he follows a particular philosopher or that he expresses and applies an authentic philosophical theory with internal terms of justification.B) He attempts to implicitly show how necessary is both the syllogisms and the arguments to rely on particular methodological principles. There is a tendency in his work to define in clear terms his issues, mainly as regards how Logic is distinguished from Ontology, as well as how they combine one another. His theological direction, however, does not allow him to be completely consistent with the philosophical material that he uses. Either way, the goal of his research is not strictly philosophical.C) Although he applies analytical elaboration and explanation of the philosophical concepts that he uses with great accuracy, he does not actually insist on them. This is probably because either he has already elaborated them in other works of his or because his readers were familiar with them. Nevertheless, he constitutes a clear example to understand what could be defined as Byzantine Logic, which is influenced by Aristotle, Porphyry and Proclus, although they are not mentioned in his texts.